Update from template. (#36)

Enables use of CircleCI contexts for CI credentials.

Author: microbit-matt-hillsdon

.circleci/config.yml

@@ -1,44 +1,53 @@
-version: 2
+version: 2.1
 
 defaults: &defaults
   working_directory: ~/repo
   docker:
-    - image: circleci/node:12.16.2
+    - image: cimg/node:14.19
+
+_steps:
+  restore_npm_cache: &restore_npm_cache
+    restore_cache:
+      keys:
+        - npm-v1-{{ .Branch }}-{{ checksum "package-lock.json" }}
+        - npm-v1-{{ .Branch }}-
+        - npm-v1-
+  save_npm_cache: &save_npm_cache
+    save_cache:
+      paths:
+        - .npm-cache
+      key: npm-v1-{{ .Branch }}-{{ checksum "package-lock.json" }}
+  configure_registry_auth: &configure_registry_auth
+     run:
+       name: Configure registry auth
+       command: echo "//registry.npmjs.org/:_authToken=$NPM_AUTH_TOKEN" >> ~/repo/.npmrc
 
 jobs:
   test:
     <<: *defaults
     steps:
       - checkout
-      - restore_cache:
-          keys:
-            - v1-dependencies-{{ checksum "package-lock.json" }}
-            # fallback to using the latest cache if no exact match is found
-            - v1-dependencies-
-      - run: npm ci
+      - *restore_npm_cache
+      - *configure_registry_auth
+      - run: npm ci --cache .npm-cache
       - run:
           name: Run coverage tests
           command: npm run test:coverage
       - run:
           name: Run build
           command: npm run build
-      - save_cache:
-          paths:
-            - node_modules
-          key: v1-dependencies-{{ checksum "package-lock.json" }}
       - persist_to_workspace:
           root: ~/repo
           paths: .
       - store_artifacts:
           path: ~/repo/dist
+      - *save_npm_cache
   deploy:
     <<: *defaults
     steps:
       - attach_workspace:
           at: ~/repo
-      - run:
-          name: Configure registry auth
-          command: echo "//registry.npmjs.org/:_authToken=$NPM_AUTH_TOKEN" >> ~/repo/.npmrc
+      - *configure_registry_auth
       - run:
           name: Publish package
           # For now we only publish on tags here and assume the version number is already correct.
@@ -50,10 +59,14 @@ workflows:
   test-deploy:
     jobs:
       - test:
+          context:
+            - "NPM Read"
           filters:
             tags:
               only: /^v.*/
       - deploy:
+          context:
+            - "NPM Write"
           requires:
             - test
           filters: